What are the Types of Dog Arthritis?
The types of dog arthritis are determined by the cause of the damage to the joint and the part of the joint that is damaged. In humans, there are over 100 different types of arthritis. Although dogs can experience many of the same forms of arthritis, there are a few common types of arthritis in dogs that owners are more likely to see.
Acute vs Degenerative Arthritis in Dogs
When most people think of arthritis, they picture joint pain gradually increasing as a dog gets older. The dog’s arthritis is a sign of aging that gets progressively worse. This is a common form of dog arthritis, and is degenerative arthritis.
There is also acute arthritis in dogs. Acute arthritis appears very quickly, or instantly. Often, acute arthritis is the result of an injury. For example, a dog jumps off a deck and twists a knee or hip. The injury is typically to the ligaments holding the bones together. They can be stretched or torn, and the result is immediate pain and swelling. Acute arthritis in dogs can also be caused by an infection, often the result of an injury or bite to the joint. In some cases, the infection may not directly damage the joint. Instead, the infection causes a buildup of synovial fluid, and the swelling stretches or tears the synovial membrane causing pain or permanent damage.
Degenerative arthritis in dogs develops slowly over time. It involves the gradual wear and tear on a part of the joint. Osteoarthritis, a very common form of arthritis in people, also affects dogs and is a degenerative arthritis. Osteoarthritis involves the gradual wearing down of the cartilage in the joint. As the cartilage wears, it stops providing the smooth surface for the bones, and ultimately degrades the bones.
Hip dysplasia is another common form of degenerative arthritis in dogs. With hip dysplasia, the ligaments that hold the bones together stretch, allowing them to separate slightly. This separation causes the bones to impact the cartilage and each other, leading to a failure of the cartilage, development of bone spurs and other problems.
Degenerative arthritis has four primary causes. First, as dogs age, they produce less glucosamine, an amino sugar critical to the building and maintaining of cartilage. As glucosamine levels drop, the dog’s body ceases to have the materials required to maintain the cartilage, and it begins to degrade. Second, dog’s with very active lifestyles will experience more wear and tear on their joints. The level of activity that is acceptable or excessive will vary by breed and within breeds. Third, the physical condition of the dog will affect the health of the dog’s joints. Diets that lack essential nutrients and obesity will increase the likelihood of a dog developing degenerative arthritis. Fourth, some dogs have a genetic predisposition toward joint problems. For these dogs, providing a healthy diet and lifestyle are not enough, and degenerative arthritis may be inevitable.
Regardless of the type of degenerative arthritis or the cause, the result is the same. The joint becomes extremely painful, and eventually, the mobility of the dog is limited.
The Role of Inflammation
Degenerative arthritis leads to wear of the cartilage and degradation of the bone. In severe cases, the pain is due to the direct damage to the bones. Prior to this, the pain is often a result of inflammation. As the joint degrades, it will become inflamed. The swelling will press on nerves and cause pain. This makes it imperative to reduce swelling in order to eliminate pain.
Interestingly, there is research that indicates that joint pain due to inflammation will lead to the degradation of other joints. The research found that the transmission of pain signals from an inflamed joint would cause an inflammation in joints along the nerve pathways. The research describes a bidirectional transmission of inflammation and pain. This would mean that a degenerative hip would cause degeneration in the adjacent knee and in the back. Based on this, dealing with arthritis pain is important not only to alleviate pain, but also to prevent problems from developing in other joints. To read more about this, check out this article in the Arthritis and Rheumatism: Spinal Interleukin-1â in a Mouse Model of Arthritis and Joint Pain
For more information:
Arthritis in Your Dog, Healthy, Happy Dogs (accessed 8/2011)
Arthritis in Dogs, Dog Obedience Training Review (accessed 8/2011)
Joint Cartilage Erosion in Dogs, PetMD (accessed 8/2011)
Canine Rheumatoid Arthritis, University of Georgia (accessed 8/2011)
